Flow Rate Based on Pressure and Pipe Size

Flow Rate Formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Inlet Pressure (P₁):

psi

Outlet Pressure (P₂):

psi

Fluid Density (ρ):

lb/ft³

Pipe Diameter:

inches

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is Flow Rate Based on Pressure and Pipe Size?

Definition: This calculator estimates fluid flow rate through a pipe based on pressure difference and pipe diameter.

Purpose: It helps engineers and technicians determine flow rates in piping systems for design and analysis.

2. How Does the Calculator Work?

The calculator uses these formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Where:

\( V \) — Fluid velocity (ft/s)
\( P_1 \) — Inlet pressure (psi)
\( P_2 \) — Outlet pressure (psi)
\( \rho \) — Fluid density (lb/ft³)
\( Q \) — Flow rate (GPM)
\( A \) — Cross-sectional area of pipe (ft²)

Explanation: The pressure difference drives the flow, converted to velocity, which is then multiplied by pipe area to get volumetric flow.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate estimation ensures proper system design, pump sizing, and process control in fluid systems.

4. Using the Calculator

Tips: Enter pressure values (psi), fluid density (default 62.4 lb/ft³ for water), and pipe diameter (inches). All values must be > 0 except P₂ which can be 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the 144 factor in the equation?
A: This converts psi (lb/in²) to lb/ft² (1 ft² = 144 in²).

Q2: Why 448.83 in the flow rate formula?
A: This converts ft³/s to gallons per minute (1 ft³/s = 448.83 GPM).

Q3: What fluid densities should I use?
A: Water is 62.4 lb/ft³, gasoline ~42 lb/ft³, oil ~55 lb/ft³, air ~0.075 lb/ft³.

Q4: Does this account for friction losses?
A: No, this is for ideal flow. For real systems, include friction factors.

Q5: How does pipe diameter affect flow?
A: Flow increases with the square of diameter (double diameter = 4× flow area).